(1) Field of the Invention
This invention relates to nonionic surfactants and methods for making the same, with particular reference to nonionic surfactant compositions comprising monohydroxy alcohols capped with a polycarbonate.
(2) Brief Description of the Prior Art
In many industrial and household cleaning applications it is desirable or necessary to use a surfactant in the cleaning formulations to achieve satisfactory wetting and cleansing. Furthermore, in many of these industrial and household applications it is necessary to maintain a low level of foam during the cleaning operation. For example, surfactants that produce excessive foaming may be unsuitable in an industrial spray metal cleaning operation or for use as an active ingredient in detergents and rinse aids for household mechanical dishwashers.
One type of nonionic surfactant known in the art is the fatty acid ester of an alcohol ethoxylate, which ester is produced by condensing ethylene oxide with a detergent range alcohol, and then reacting such ethoxylated alcohol with fatty acids containing from 8 to 18 carbon atoms, or with the chlorides of such acids. Surfactants produced in this manner are described in U.S. Pat. No. 1,970,578 which teaches such surfactants as having excellent wetting, foaming and cleansing properties. However, surfactants of this type would not be satisfactory for uses where the suppression of foam is important.
Another type of nonionic surfactant known in the art is described in U.S. Pat. No. 3,539,518 which teaches a low foam, nonionic surfactant composition consisting essentially of a straight chain acyl group of 1 to 5 carbon atoms capped on an alcohol ethoxylate. More specifically the low foam surfactant composition consists of an alkoxypolyethoxycarboxylate compound which is produced by condensing ethylene oxide on an alcohol having 4 to 20 carbon atoms using means well known to the art, and then reacting this ethoxylate with a straight chain alkanoic acid having 1 to 5 carbon atoms or with the acyl halide or the anhydride of such acid.